Acetazolamide plus low-dose dexamethasone is better than acetazolamide alone to ameliorate symptoms of acute mountain sickness

Aviat Space Environ Med. 1998 Sep;69(9):883-6.


Methods: In a double-blind study, we compared the efficacy of a combination of sustained-release acetazolamide and low-dose dexamethasone and acetazolamide alone for prophylaxis against acute mountain sickness (AMS) caused by rapid ascent to high altitude. Before ascent, 13 subjects were randomly assigned to receive a combination of one sustained-release acetazolamide capsule (500 mg) in the afternoon and 4 mg dexamethasone every 12 h, or a combination of the same dose of acetazolamide once daily and a placebo every 12 h. Days 1 and 2 were spent at 3698 m (La Paz, Bolivia), while days 3 and 4 were spent at 5334 m (Mount Chaclataya, Bolivia). Ascent was by 2 h motor vehicle ride. Heart rates, peripheral oxygen saturations and a modified score derived from the Environmental Symptom Questionnaire (modified-ESQ) were measured on each day. In addition, weighted averages of the cerebral (AMS-C) and respiratory (AMS-R) symptoms were calculated for days 3 and 4.

Results: Heart rate and modified-ESQ scores increased on days 3 and 4 compared with the other days in the acetazolamide/placebo group only (p < 0.05). Oxygen saturations decreased in both groups on days 3 and 4 (p < 0.05), but the decrease was greater in the acetazolamide/placebo group (p < 0.05). AMS-C and AMS-R scores rose above the suggested thresholds for indication of AMS on days 3 and 4 in the acetazolamide/placebo group only (p < 0.05).

Conclusion: We conclude that this combination of sustained-release acetazolamide once daily and low-dose dexamethasone twice daily is more effective in ameliorating the symptoms of AMS than azetazolamide alone at the ascent that was studied.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Acetazolamide / therapeutic use*
  • Acute Disease
  • Adult
  • Altitude Sickness / metabolism
  • Altitude Sickness / physiopathology
  • Altitude Sickness / prevention & control*
  • Anti-Inflammatory Agents / therapeutic use*
  • Blood Gas Analysis
  • Delayed-Action Preparations
  • Dexamethasone / therapeutic use*
  • Diuretics / therapeutic use*
  • Double-Blind Method
  • Drug Therapy, Combination
  • Female
  • Heart Rate / drug effects
  • Humans
  • Male
  • Severity of Illness Index
  • Surveys and Questionnaires


  • Anti-Inflammatory Agents
  • Delayed-Action Preparations
  • Diuretics
  • Dexamethasone
  • Acetazolamide